The answer in the comment above is correct. You need to be able to draw a vertical line through the given choices. The vertical line intercepts two point (and only 2 in this case) which are on opposite sides of the x axis. They must also be an equal distance from the x axis.
One the points must be minus and the the other plus. The value must be the same. Only the sign can be different. The answer that fits all that is x = -2.
